Vitamin D has an important immunomodulatory effect, but there are no trials that directly address the boosting of serum levels of 25-hydroxyvitamin D (25[OH]D) in juvenile-onset systemic lupus erythematosus (SLE). The aim of this study was to evaluate the effect of vitamin D supplementation on disease activity and fatigue in juvenile-onset SLE.

This study was a randomized, double-blind, placebo-controlled, 24-week trial. Forty juvenile-onset SLE patients were randomized (1:1) to receive oral cholecalciferol 50,000 IU/week (juvenile-onset SLE-VitD) or placebo (juvenile-onset SLE-PL). Medications remained stable throughout the study. Serum levels of 25(OH)D were measured using radioimmunoassay. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and the European Consensus Lupus Activity Measurement (ECLAM). Fatigue was assessed using the Kids Fatigue Severity Scale (K-FSS).

At baseline, groups were similar regarding age, body mass index, organ involvement, glucocorticoid dose, use of immunosuppressive drugs, SLEDAI, ECLAM, K-FSS, and levels of 25(OH)D. After 24 weeks, the mean level of 25(OH)D was higher in the juvenile-onset SLE-VitD group than in the juvenile-onset SLE-PL group (P < 0.001). At the end of the intervention, a significant improvement in SLEDAI (P = 0.010) and in ECLAM (P = 0.006) was observed in the juvenile-onset SLE-VitD group compared to the juvenile-onset SLE-PL group. Regarding fatigue evaluation, a reduction of fatigue related to social life score was found in the juvenile-onset SLE-VitD group compared to the juvenile-onset SLE-PL group (P = 0.008). Cholecalciferol was well tolerated with no serious adverse events.

This study suggests that cholecalciferol supplementation for 24 weeks is effective in decreasing disease activity and improving fatigue in juvenile-onset SLE patients.